First, I will make a caveat. Then, I will froth. Then, I will find the silver lining which makes this all better.

Caveat:

This is a delicate situation here. I love kids, and I love kids who love astronomy. I want to foster that love, and turn it into a lifelong interest in the sky, in astronomy, and in science.

Froth:

So having said that, what the heck was National Geographic thinking?

They held a contest for kids to come up with a mnemonic, a memory-aid device, to help them remember the order of the planets. Like, My Very Excellent Mother Just Served Us Nine Pizzas, which is the one I heard when I was younger.

I’m all for this. That’s a great idea. Except… in the rules it says this (emphasis mine):

Compose a mnemonic (memory trick) using the first letter of each of the planets in order from the Sun (Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Eris) as the first letter in a word. The words must make a fun and memorable English sentence (Example: My Very Excellent Mother Can Jump Slowly Under Nelly’s Plastic Elephant.)

Um, NatGeo? I hate to break it to you, but our solar system, officially, has eight planets. Pluto was kicked out years ago. If you want to be a Luddite and still accept Pluto as a planet, that’s fine, but really, Ceres and Eris too?

Nope.

Eris is an object similar to Pluto, but slightly bigger and more massive, well out past Neptune’s orbit (objects there are usually called Kuiper Belt Objects or KBOs). While it fits some of the new definitions of a planet, it doesn’t clear out its neighborhood of smaller objects (it’s too small, and the space it occupies out in the hinterlands of the solar system are too voluminous), and that’s one of the rules planets follow.

Same with Ceres, the largest asteroid. With thousands, millions, of asteroids in the same region of space, Ceres doesn’t hack it either. Besides, all three objects (Ceres, Eris, and Pluto) are smaller than our own Moon. If you include those three, there will be dozens more, hundreds more, you have to include as well. You might even have to include Pluto’s moon Charon (note; some of the things I said in that post were superseded by later rules imposed by astronomers on the definition of a planet).

So in the end, NatGeo would have done a lot better to leave Ceres and Eris off — they’re just not planets by anyone’s definition — and to be consistent they should have left Pluto off as well.

It’s cute and it’s memorable (and it certainly follows the rules of the contest).

And in reality, what is very cool about this is we now have a little girl out there in Montana who not only knows the order of the planets, but she also knows a little something about asteroids and KBOs, too. How many ten-year-olds can say that? And I wonder, what’s in her future? Maybe eventually she’ll take an interest in the planet-naming controversy and help settle it. Maybe she’ll grow up to be an astronomer who discovers Earth-like planets orbiting other stars.

Where will her interests lead? For now at least, they’ve taken her billions of kilometers to the edge of the solar system, and for that, I am glad, and I congratulate National Geographic on holding the contest and doing something terribly, terribly important: igniting a spark for science.

Tip o’ the Whipple Shield to BABloggees John Phillips, Jeromy Labit, and Richard Velez for emailing me about this!

In french we had our line too… “Mon vieux tu m’as jeté sur une nouvelle planète”… Now that one doesn’t work too either. And it’s not a bad thing, because I always thought as a kid that this was the most retarded line. I mean, I knew the one in english. It spoke of pizza. That was awesome. Ours spoke of a dude that threw another dude on a new planet. That’s lame.

I quizzed my niece and her friend about the order of the planets when they were 11 and they did not need a mnemonic. When I raised my eyebrows after Neptune, I got a wag of the finger and she said, “Nuh uh uh, pluto isn’t a planet!” So, they learned that in 6th grade (at a Catholic school, btw.)

Off topic: Her current science teacher is strict. When she skipped a line on a test, she got 50 points off, which I think is harsh for a minor thing. The teacher said that in real life there are consequences for such mistakes (like messing up with the metric system?). I was thinking, hey, don’t turn these kids off from science. They also learn about gas and matter in kindergarten, which was not my experience at all.

What’s wrong with including dwarf planets in the mnemonic? Seems like a diplomatic solution to me, and the IAU currently only recognizes Ceres, Pluto and Eris as dwarf planets. Once Charon and Sedna and all those other crazy TNOs get grandfathered in, we could have a very complicated mnemonic indeed, but in the meantime let’s just congratulate little Maryn on her clever turn of phrase. Lisa Loeb’s supposedly going to even write a song using the mnemonic as part of the prize, which is probably pretty cool for a ten-year-old girl.

Uh BA, that’s because the IAU is made up of imbeciles who misdefined the word planet. I hope that in a few years that STUPID definition gets overturned. That definition is so odd that it is possible to alter Earth’s orbit and then have it be declared a non-planet. Whether something is a planet or not should have nothing to do with its orbital state.

*kicks the IAU in the nads*

Here’s what the IAU should have decided:

1) “Classical Planet” – The 9 planets defined in a classical sense. Before this point the word ‘planet’ had no exact meaning, so these planets are defined as nothing more than “this is what people use to call planets”. This applies to only those 9 specific objects, and only to the Sol system. It exists for linguistic and historical purposes only, holding no scientific meaning.

2) “Planet” – An object that is gravitationally bound to a star that is:

i) large enough to be approximately spherical due to its own gravity.

ii) small enough that it is incapable of undergoing deuterium fusion.

(values of mass and “sphericalness” would be given exactly)

3) “Rogue Planet” – an object that meets the above criteria but is not gravitationally bound to a star.

I really don’t understand what’s so bad about having a zillion planets. It’s not like we’d really have to memorize them all. We have a zillion stars, and no one asks us to memorize all of them… even the most obsessive amateur might pick 25 of the brightest or nearest and be perfectly content. And even reference books stop at 100 unless they are the size of rooms.

Secondly, Pluto not being a planet is hardly settled. The whole notion of “dwarf planet” is linguistically malconstructed. I mean seriously, it’s not SUPPOSED to have anything to do with their size, and here Phil is talking about how they are too small. And what will you do if a hypothetical KBO the size of Mars is discovered (such an object has been predicted). The current nomenclature will call it a “dwarf planet”, and will it still be too “small” if it’s the size of Mars? And what makes Mercury big enough? I mean, it’s just a rock, right? Why this magic cut-off?

Planet was perfectly fine, like species or language, with some vague definition and everyone “knew” what it was. Now they’ve just gone and mucked it up. So until someone gives me a GOOD reason to think Pluto and Eris aren’t planets, they are still going to be planets to me. I don’t have any weird snobbery about planets being “special” which is what I think this whole controversy comes down to. At least they both have moons.

I maintained, starting back in the ’80s, that Ceres should be counted as the planet between Mars and Jupiter. Indeed, I got reprimanded for it by an anonymous reviewer from Icarus.

I like the 11-planet system (eight planets, three dwarf planets) because it preserves the spacing ratios nicely. If you leave out Ceres, you have this huge, weird gap between Mars and Jupiter. (Okay, in terms of mass, there really is a huge, weird gap between Mars and Jupiter, but it’s the principle of the thing.) And at 67 AUs, Eris is neatly positioned outside Pluto at 40 AUs. (I’m talking semimajor axis, not present distance.) The 11-planet system lends itself to “improved” versions of Bode’s Law.

I memorized them by rote around 5 and also got into arguments by claiming pluto wasn’t a *real* planet – not that I refused to list it but just, well, that’s one screwed up orbit for a planet to have.

Now, I seem slow reciting them because I have them in rote in the wrong language, my brain recites them in the other language internally and then I translate them, stumbling slightly. It’s the same with the first 15 decimals of pi, I know the words to say them in the wrong language and then stumble because I forgot where I were when saying them in english.

I prefer mnemonics with *two* first letters though (yes, I’m that scatterbrained – need more then one letter for clues) like “Men very easily make cement, juniper sauce urges net plot errors.”. I do better with less reasonable sentences but which provide additional clues when going “J.. j.. what starts with J again?”.

I’m always surprised to hear so many people with scientific minds stand so hardcore on Pluto. I mean, is not part of the scientific process that we adjust based on what we see? That said…

Someone early said something about keeping Pluto as a planet until there was a good reason not to do so. I always considered that the “good” reason to dismiss Pluto as a planet was that it really more at home with another classification of bodies, KBOs, given it’s location, composition and orbit, just as Ceres fits the classification of asteroid particularly well. Just my two cents.

What happened to Sedna? When it was discovered a few years ago, it was billed as the tenth planet. Then Pluto got kicked out, and suddenly it seemed like the whole dang solar system went to sh*t. And is it a coincidence that it happened during Bush’s presidency? I think not.

I thought my son was a little behind, because he couldn’t name all the planets until after he was four. Now he’s almost five, and he can tell you something about all of them – which one’s the hottest, which one’s the largest, which ones have rings, etc. (He knows a few of the elements and a lot of states, too.) If my wife and I were obsessive parents and spent all day forcing him to learn, I’d think we should ease up.

One of his favorite things to tell my wife is “I love you all the way to the Andromeda Galaxy and back.”

Don’t forget that the IAU’s highly political taxonomy of planets not only is inapplicable beyond our solar system but also, applied consistently, demotes Jupiter, which is apparently “unable” to clear the trojan asteroids from it’s orbit. Someday, everyone but flat earther’s and disgruntled planetary dynamicists will get used to the idea of thousands of planets.

My Astronomy lecturer at Uni in the 90’s used to deduct points if we said Pluto was a planet in quizzes and exams. Yeah there are probably hundreds of planets out there if you don’t want to take the strict abriarty (sp) route that IAU did but I’m not too fussed because at least the kept the mnemonic fairly simple to learn.

At school we were taught, “Mrs Vokes eats many jam sandwiches until nearly pops” which was very memerable for us as we had a very rubenesque (sp) maths teacher called Mrs Vokes.

“Don’t forget that the IAU’s highly political taxonomy of planets not only is inapplicable beyond our solar system but also, applied consistently, demotes Jupiter, which is apparently “unable” to clear the trojan asteroids from it’s orbit.”

That’s hardly fair. You’re not supposed to be able to clear objects at L4 and L5.

It would upset a bunch of european astronomers if we continued to call it a planet.

Somehow, I don’t think this topic has been settled yet. In 12 more years, when Far Horizon arrives there and (we hope) gets a few good photos of some of the last terra incognita the solar system has, I think the argument will be renewed.

Something just occurred to me: this article is about a *girl* who’s interested in science. We probably shouldn’t discourage that. Granted, she probably isn’t going to read this web page, but just in case…

Isaac Asimov stated that the Solar System consists of “four planets plus debris” (often misquoted as “Jupiter plus debris”, which I prefer). So that’s that.

But apart from that, I’m with Betsy on this; we have names for hundreds (thousands?) of stars, so why can’t we have dozens or even hundreds of planets? If it’s spherical (more or less), and goes round the sun, it’s a planet. Knowing their order really isn’t as important as knowing that they exist at all as far as children’s education is concerned, and anyway if we keep changing our minds about things like this, it only gives ammo to the Anti-Science brigade who say “See? The scientists are always changing the facts! So it’s obviously all made up.”

Anyway, I wrote some music about Pluto and Charon, so it stays a planet in my book. It’s part of the culture, so it has to be.

Ceres and Eris are cool chunks of matter. I mean, they’re not the greatest, but they’re worth making kids learn about for all the reasons they’re NOT “planets”. There’s no reason kids can’t handle the idea of KBOs and the asteroid belt between Mars and Jupiter. Named objects put a friendly face on astronomy (something humans have been doing for thousands of years). The factoids associated with them are also the kind of stuff kids eat up.

I hate the exclusion of round objects of planets. Basically, they could not hope to memorize all of the planets, so they exclude most of them. The best thing is that if one considers a moon as some fitting the round part of the definition but orbiting the another planet. This would nicely tell us when to stop. If not, then we shall have to name the gzillions of chunks of ice in the rings of Saturn as moons.

We do need mnemonics any more. We needed them before we could visualized planets. Back then, planets were nothing more than a list of names. Now, planets are worlds. When I heard Neptune, I see Neptune in my head. Just show the children pictures about the planets as they learn them. Frankly, these meaningless mnemonics are harder to remember than just imagining the Solar System on a logarithmic scale with a picture of each planet enbiggened logarithmically. That is what I do.

I live on Ceres and support your “National Geographic”. You should, too, as they are your food source (if our studies are correct). Please forgive any mistakes, we just got the internet this week and my eye transponder is still buggy.

Hal Levison made an error in the first sentence of his paramaterizaion of the definition. According to the IAU, a planet is a celestial body that:

– is in orbit around the Sun,
– has sufficient mass so that it assumes a hydrostatic equilibrium (nearly round) shape, and
– has “cleared the neighbourhood” around its orbit.

Levison rephrased that third part of the definition as an “object large enough to clear its neighborhood of small bodies”.

The problem is that the IAU used the past tense (that the body has already cleared the neighbourhood), whereas Levison is stating a potential (that it possibly could).

According to the strictest interpretation of the IAU definition, there are only two planets in the universe: Saturn and Uranus. Extrasolar planets are not planets, because they don’t orbit the Sun. Mercury, Venus, Earth, and Mars have not yet cleared their neighborhoods of asteroids. Jupiter has trojan asteroids. Neptune has not cleared Pluto from its orbit.

Well, that’s sort of the point, LabLemming. The IAU’s definition is extremely vague, and includes terms like “clearing the orbit” that mean less than the term “planet” used to mean. In their zeal to exclude Pluto from the definition of planet, they have made the situation even worse than it was before. If one follows the letter of their definition, then even frikkin Jupiter isn’t a planet anymore, nor are the 275 or so extrasolar planets found thus far.

I have to agree with Ed here. The IAU’s definition just made things worse, not better. I think having a strict definition of planet makes no sense, since any definition that we make will result in some object, somewhere eventually being so close to the line between planet and something else that people are going to want it to be changed.

As I’ve already said, I think the IAU’s decision to “demote” Pluto is warranted, as it really does appear to be a KBO, just as Ceres was reclassified as an asteroid in 1802.

@Elwood: ‘…and anyway if we keep changing our minds about things like this, it only gives ammo to the Anti-Science brigade who say “See? The scientists are always changing the facts! So it’s obviously all made up.”’

But that’s part of science! Updating and changing old ideas to represent a better understanding of the data is supposed to be central in scientific pursuit. When Pluto was discovered, it made since to call it a planet. But as time has gone on, we’ve discovered that Pluto isn’t this lonely little odd planet at the fringe of the solar system, but instead, part of another class of objects. Is it still worthy of recognition and the money it takes to study it? Heck yeah! But refusing to accept that Pluto really fits into the KBO classification better then the planet classification just because it clashes with existing world views? Isn’t that the kind of thinking that people like BA are fighting when they speak out against the Anti-Science brigade?

Aerimus:”Pluto really fits into the KBO classification better then the planet classification”. The dubious assumption being that it couldn’t possibly be in both classifications. I have no problem with the term “dwarf planets” as long as it also includes Mercury, Venus, Earth and Mars. That’s where the obvious size break occurs, and isn’t the word “dwarf” about size?

On Saturday, March 15th, 2008 from 4-5PM, 826 Seattle and Greenwood Space Travel Supply, located at 8414 Greenwood Avenue North, are protesting the 2006 International Astronomical Union’s reclassification of Pluto as a “dwarf planet.” This event is free and open to the public.

826 Seattle is the city’s only writing center entirely dedicated to helping students, ages 6 to18, improve their written communication skills. All 826 programs are structured around the belief that great leaps in learning can happen with one-on-one attention and that strong writing skills are fundamental to a young person’s future success. With the help of hundreds of volunteers, 826 Seattle offers free after-school tutoring, special writing workshops, class field trips, in-school programs, and publishing opportunities for Seattle students to improve their ability to communicate effectively in writing. 826 Seattle is supported in part by the Greenwood Space Travel Supply storefront.

The “Pluto IS a Planet” protest march and rally is the culmination of a two-day persuasive writing workshop geared towards youth ten years and older. The march begins at The Greenwood Space Travel Supply Co., travels north on the sidewalks of Greenwood Avenue to 87th Street, and returns south at Neptune Coffee, located at 8415 Greenwood Ave North. At the rally, before a panel of experts, workshop participants will read their persuasive arguments as to why Pluto should be reclassified as a planet. Experts include professional persuasive author, Seattle Times columnist Nicole Brodeur, professional persuasive speaker, lawyer Shawn Rediger, and local rocket scientist Tim Lloyd.

# # #

For more information, please contact Justin Allan, Store and Events Manager at (206) 725-2625 or go to http://www.826seattle.org.

Yeah, Pluto could be defined as both, as well as Eris and Ceres. I just think that things as they are now work better when you consider Ceres to be an asteroid (based on size, composition and location relative to other asteroids), Eris and Pluto as KBOs (again, based on the same). Then Mercury, Venus, Earth and Mars as terrestrial planets (as they are rocky worlds in areas that are, relatively speaking, empty and located closer to the center what was once the proto-planetaru disk, where the heavier elements that make them up would be expected) and Jupiter, Saturn, Uranus and Neptune as the gas giants (with their own traits and characteristic that should be obvious).

So far, the biggest reason that I’m always hearing as to keeping Pluto a planet is always more of a dogmatic answer rather than one based on observations or data (i.e. “Pluto will always be a planet to me!”). Maybe I’m just not listening to the right people, or the right people’s voices are being drowned out be the swaft of uneducated people who just cry “Pluto will always be a planet to me!” (as a Christian who believes in a figurative genesis and that religion should be changed to support science discovers, I know how that feels). Maybe when the essays in Seattle are done, they’ll post some. I think that it’s marvelous that they are getting kids to look at this critically, even if it is in opposition to my personal preference. I’m just hoping that the essays, at least from the high schoolers, have some real thought behind them.

Some other things:
1) Concerning Jupiter clearing out it’s orbit arguement – This is specifically why I think that the definition is poor or should be dropped altogether and we just look at all this planet crap on a case by case basis. Yeah, there as asteroids in Jupiter’s orbit which have not been “cleared out”, but they are being herded by Jupiter’s gravity. It’s clear who in control in Jupiter’s neighborhood.
2) Yeah, if we want to pick nits, the definition only applies to the solar system. But come on! Like you can’t easily take this definition and use it when looking at other systems? Wow, that’s narrow minded.

I think that the kicker question is this: If Pluto were found today, knowing what we know now about KBOs, would it be a planet? I doubt it. The only reason why Eris is being questioned about planet or KBO is because its larger that Pluto.

When I was young, and the solar system was an orderly, simple place, I had a good one for remembering the order of the “classical” nine planets. Mount Vesuvious Erupts Mulberry Jam Samwitches Under Normal Pressure.

National Geographic was thinking what the IAU should have thought–what makes linguistic and scientific sense, namely that dwarf planets should be classified as a subclass of planets. These objects are significantly different from the asteroids in that they have achieved hydrostatic equilibrium, meaning they have enough self-gravity to pull themselves into a round shape, giving them geological processes more akin to those of the classical planets. Many planetary astronomers concur with this view and oppose the IAU definition, which was coined by four percent of its membership, most of whom are not planetary scientists.

At this time, when we are discovering more types of exoplanets than we could have imagined, we should be broadening, not narrowing the concept of planet. If that means we have 200 planets in our solar system, then so be it. Memorization is not as important as is understanding the characteristics of the different types of planets. So we could divide the broad term planet into subcategories such as terrestrial planets, gas giants, ice giants, dwarf planets, etc. Yet all would still be planets. This classification would acknowledge the significant differences between inert, shapeless asteroids, and objects like Ceres, Pluto, and Eris that have achieved hydrostatic equilibrium.

Telling people to “get over” a decision we believe is scientifically wrong and was established by a closed, backroom process is ridiculous and nothing more than a personal attack, which is what people make when they have no arguments to back up their viewpoints.

As for the 11-year-old in Catholic school being taught that we have only eight planets, she and her classmates are not getting the whole truth, which is a disservice to them. Children can understand that some debates remain open, that different experts can observe the same facts and reach different conclusions. Teaching only one view is teaching dogma, plain and simple. Schools should use this opportunity to help children learn that some issues are open-ended and have more than one answer and that the process by which decisions are made are as important as those decisions themselves.